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The SirBot Ranger

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Based on the Tamabot Daycare architecture, the SirBot Ranger (aka Chuck Nobbot), is able to provide detailed information about its environment: using its GP2D02 IR distance ranger,  the SirBot Ranger is able to draw 2D maps.

Let's see how it works !

Note: the following examples are based on an old SirBot architecture, never released. Some information may be obsolete... Have a look at this post entry, to see how the SirBot Ranger is now built using the released version of SirBot.

The Scene


In order to see all the great capabilities of the SirBot Ranger, we need to build a scene so it can measuse some stuffs... Because the SirBot Ranger loves fruits, let's put some of on a table, as follows:


the_scene_with_fruits.png



the_scene_without_fruits.png


Here's what it looks like in reality:

the_scene.jpg


OK, the scene is ready, now we can order the SirBot Ranger to analyse the whole... To do such, we program it so it takes measure from point A, to point B, for each steps available while rotating the servo (that, here 32 steps). The program is simple:

the_program.png

The program sets the starting position (servo to position 10, that is point A), takes 3 times a range (we mean the values), rotates by one step the servo, takes 3 times a range, rotates, etc... until the servo position reaches 42 (end of the scene, point B). And, yes, there are no for loops in SirBot... Note: SirBot 0.1 now has for loops, and many more, since it's fully python-based...

For this current version of the SirBot Ranger, results (distances, angle) are displayed on the screen. Note distances are automatically converted the GP2D02 IR ranger, and displayed in cm (see the IR Ranger board for more details):

the_results.png

The whole process is done when fruits are on the table, and when fruits aren't. Grepping, sedding the resulrs, and feeding gnuplot finally gives the following results (amazing!):

the_scene_by_ranger.png


Yes !!! The fruits are detected ! But distances are definitely wrong... The SirBot Ranger is myope !!! Here a little video of this scene:




How to build it

Hardware


To get a fresh SirBot Ranger, you need 3 major boards:
  • a Main Board, which handle communication between the bot and the PC, and have a power supply
  • a Servo Controller Board, which can control up to 8 servos (one actually beeing used here)
  • a IR Ranger Board, to connect the GP2D02 IR ranger to the whole.

The whole is connected thanks to the famous bus cable. The following diagram shows how to assemble those boards:


build_schema.jpg


You also need to metal frame, directly derived from the Tamabot Daycare one. You can also have a look on the galley, later on this page.


Software


As usual, two pieces of software are needed (available at the SirBot Project page):
  • a PIC ASM file containing all handled actions, specifically the code need to activate the GP2D02 IR ranger, and get its results
  • a protocol file, used by the SirBot console to communicate with the SirBot Ranger.

Gallery


Some pictures of the SirBot Ranger.


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